Organic phosphorus compounds



United States Patent ORGANIC PHOSPHORUS COMPOUNDS Earl G. De Witt, RoyalOak, Mich., assignor to Ethyl Corporation, New York, N. Y., aCorporation of Delaware No Drawing. Application November 16, 1953 SerialNo. 392,453

2 Claims. (Cl. 260-461) The present invention relates to a class oforganic compounds containing phosphorus, sulfur and bromine. Inparticular, the present invention relates to organic esters ofphosphorus having particular utility in the chemical arts.

It is known that phosphorus forms compounds with organic radicals which,can be considered as derived from phosphorus acids. In particular, themonomeric phosphorus acids form organic esters generally classifiable asphosphites and phosphates. It is further known that in such phosphite orphosphate esters of monomeric phosphorus acids one or more of the oxygenatoms directly bonded to the phosphorus can be replaced by sulfur. Suchesters can be described by the terms thiolophosphite and thiolophosphatewhen oxygen is replaced by divalent sulfur, and as thionophosphate whenoxygen is replaced by semi-polar sulfur. Likewise, the correspondingthiolothionophosphates are known. In such terminology the expressionthiono refers to semipolar sulfur to distinguish from divalent sulfur.Certain derivatives of the above-mentioned esters of phosphorus havebeen proposed wherein the organic radical is substituted with chlorine.In particular it is known that chloroalkylphosphates,chloroalkylphosphites and sulfur-containing derivatives thereof can beprepared and have found certain utility in the art.

It is an object of the present invention to provide organic compounds ofphosphorus containing sulfur directly bonded to phosphorus and brominedirectly bonded to the organic portion of the molecule. It is a furtherobject of this invention to provide a class of organic chemicalcompounds having wide utility and advantages over organic phosphoruscompounds previously known and described. A further object is to providealiphatic esters of phosphorus-containing sulfur directly bonded tophosphorus and bromine directly bonded to the aliphatic portion of themolecule. Still a further object is to provide 3-bromoaliphatic estersof phosphorus acids in which sulfur is directly bonded to phosphorus.These and other objects will become apparent from the furtherdescription hereinafter.

The above and other objects of this invention are accomplished byproviding bromoaliphatic esters of sulfurcontaining monomeric acids ofphosphorus wherein said sulfur is directly bonded to phosphorus. Apreferred embodiment of my invention comprises those compounds in whichthe aliphatic group is alkyl.

The bromoaliphatic esters of sulfur-containing monomeric acids ofphosphorus of this invention are derived from the monomeric trivalentand pentavalent acids of phosphorus. Thus, I have providedbromoaliphatic sulfur-containing phosphites and bromoaliphaticsulfur-containing phosphates. Both examples of the compounds of thisinvention can be prepared by reacting cyclic derivatives of olefins withphosphorus bromides.

The compounds of my invention find utility as chemical intermediates,plasticizers, flameproofing agents, fuel and oil additives, and thelike.

One example of the phosphites of this invention comprise thep-bromoaliphatic thiolophosphites wherein at least one aliphatic radicalis directly bonded to phosphorus through sulfur. It is furtherunderstood that this embodiment of the compounds of this inventioncomprises the mono-, diand tri-thiolophosphites. The aliphatic groups ofsuch thiolophosphites can be the same or different and can be normal oriso with respect to the linkage of the alkyl radical to phosphorusthrough sulfur or oxygen. p

In general, the above tri-thiolophosphites are prepared by reacting acyclic sulfide of an olefin with a phosphorus bromide. In one embodimentof this invention ,S-bromoaliphatic thiolophosphites are prepared byreacting a cyclic aliphatic sulfide (which, however, can be substitutedwith aryl'or other groups) with phosphorus tribromide, as shown :by thefollowing equations:

(II) 3RQIi/CH: PBr (ROHS):P

wherein R is an organic radical.

As noted above, the cyclic sulfide linkage can be severed in either oftwo positions. Depending upon the method of cleavage, the aliphaticgroups can be considered as normal or iso. Thus, in equation I theinvention is represented as providingtri-(B-bromo-n-aliphatic)trithiolophosphite and in accordance withEquation II there is formed the tri-(3-bromoisoaliphatic)trithiolophosphite. In general the iso compound willpredominate but the relative proportion of the two isomers will dependupon the severity of the reaction conditions. Thus, it is also possibleto provide a mixture of normal and iso products attached to phosphorusthrough sulfur. Typical examples of materials of this invention formedin accordance with the above equation includetri-(fi-bromoethyDtrithiolophosphite;tri-(,B-bromo-n-propyl)trithiolophosphite; tri- (fl-bromo-n-butyl)trithiolophosphite; tri-(,B-bromo-namyl)trithiolophosphite;tri-(B-bromo-n-hexyl)trithiolophosphite;tri-(B-brorno-n-heptyl)trithiolophosphite; tri- (B-bromo-n-octyltrithiolophosphite; tri-(fi-bromo-n-nom yl trithiolophosphite;tri-(fibromo-n-decyl) trithiolophosphite;tri-(B-bromo-n-dodecyl)trithiolophosphite; tri-()3--bromo-n-tridecyl)trithiolophosphite;tri-(B-bromo-n-octadecy1)-trithiolophosphite; tri-2-bromo-3-methylbutyl) trithiolophosphite; tri- 2-bromo-3 -ethylbutyl)trithiolophosphite; tri-(2-bromo-3-ethylpentyl)trithiolophosphite;tri-(ot-methyl-fl-bromoethyl)trithiolophosphite;tri-(a-ethyl-fi-bromoethyl) trithiolophosphite; tri-(a-ethyl-fi-bromoethyl trithiolophosphite; triu-propyl-fi-bromoethyl)-trithiolophosphite; tri-( u-butyl-B-bromoethyl -trithiolophosphite;tri-(a-isobutyl-p-bromoethyl)trithiolophosphite; tri-(a-sec-butyl-fl-bromoethyl)trithiolophosphite; tri-(a-a'myl-B-bromoethyl)trithiolophosphite; tri(a-isoamyl-,8-bromoethyl)trithiolophosphite; tri (u sec amyl B bromoethyl)trithiolophosphite; tri(a tert amyl [3 bromoethyl) trithiolophosphite; tria-hexyl-p-bromoethyl)trithiolophosphite; tri-( u-heptyl-p-bromoethyl) trithiolophosphite;tri-(ametyl-B-bromoethyl)trithiolophosphite; tri-(anonyl Bbromoethyl)trithiolophosphite; tri (a decyl- ,8bromoethyl)trithiolophosphite; tr'i (a dodecyl ,8 bromoethyl)trithiolophosphite; tria-tridecyl-fi-bromoethyl)trithiolophosphite; andthe like.

By proper choice of reactants there also are prepared thiolophosphitesof the present invention wherein only one or two of the alkyl radicalscontain bromine in the beta position while the other radicals containchlorine in the beta position. To provide such compounds a cyclicsulfide of an olefin is reacted with PCl Br or 'PCIBr In the formerinstance the product is predominantly monobromodichloroaliphatictrithiolophosphite. In the latter instance the product will predominatein the monochlorodibromoaliphatic trithiolophosphite. T ypical examplesof such embodiments of the compounds of this invention includedi(:fl-bromoethyl)-(,3-chloroethyl)- trithiolophosphite; di(flbromo-n-propyl)-(/3-chloro-npropyl)trithiolophosphite;di(,B-bromoisopropyD-(B-chloro-n-propyl) trithiolophosphite; di(fi-bromoisopropyl) -(fi- .chloroisopropyl) trithiolophosphite; fl-(bromo-n-hexyl di-(fi-chloro-n-hexyl)trithiolophosphite;fl-(bromo-n-decyl)-di-([3-chloro-n-decyl)trithiolophosphite; di(a-OCtYldecyl)-(;'3-chloroethyl)trithiolophosphite and the like.

Further examples include di(fi-bromoethyl) (fi-chloro-'hexyl)trithiolophosphite; (B bromoethyl)-di-(,8-chloroethyl)trithiolophosphite; (B-bromoethyl -difl-chloro-npropyl)trithiolophosphite; (fi-bromoethyl -difl-chloroisopropyltrithiolophosphite; fi-bromoethyl (IS-chloron-propyl)(fi-chloroisopropyl) trithiolophosphite; B-bromo-n-propyl) -di-(fl-chloro-n-amyl) trithiolophosphite; di- (fi-bromo-n-amyD-(fichloro-n-amyl)trithiolophosphite; (fi-bromo-n-butyD-di-(fi chloro nbutyl)trithiolophosphite; di(2-bromo-3-cyclol1exyl-n-propyl) (5chloro-npropyl)trithiolophosphite; (2-bromo2-phenylethyl) di-(2-chloro-2-phenylcthyl)trithiolophosphite and others.

In like manner the bromoaliphatic esters of sulfur-containing monomericacids of phosphorus comprise the monoand dithiolophosphites. Inproviding these examples of compounds of this invention a mixture ofolefin oxide and olefin sulfide is reacted with the phosphorus bromide.Thus, by reacting a mixture of olefin oxides and olefin sulfides withphosphorus tribromide, the products includetri-(B-bromoaliphatic)monothiolophosphate andtri-(,B-bromoaliphatic)dithiolophosphite. Reaction of a mixture ofoxides and sulfides with mixed phosphorus trihalide, such as PCI Br andPClBr yields the product with mixed halogens. Examples of this type ofcompound include tri-(fi-bromoethyl)dithiolophosphite; tri-(fl-bromoethyl)monothiolophosphite; tri-(fi-bromoisopropyl)dithiolophosphite; difl-chloro-n-propyl)(B-bromon-propyl)dithiolophosphite; di-(B-chloro-n-propyl)(pbromo-n-propyl)monothiolophosphite;di-(fl-bromo-n-propyl)-(fl-chloro-n-propyl)dithiolophosphite;di-(fi-bromon-propyl) B-chloro-n-propyl) monothiolophosphite; di- (;3bromoisopropyl) (13- chloroisopropyl)dithiolophosphite;difi-bromoisopropyl) B-chloroisopropyl) monothiolophosphite;difi-bromo-n-octyldecyl) fi-chlorooctyldecyl dithiolophosphite;difi-bromo-n-octyldecyl) (,8- chlorooctyldecyl)monothiolophosphite;di-(B-bromoethyl)-(B-chloro-n-propyl) dithiolophosphite; and di-(S-bromoethyl)-(fl-chloro-n-propyl)monothiolophosphite.

In addition to the fl-bromophosphites as described above, thecorresponding compounds, in which the bromine atom is on another carbonatom of the aliphatic group, are also contemplated by my invention.These compounds can be made, for example, by reaction of the appropriatehalohydrin with phosphorus trihalide. Compounds of this type includedi-(y-chloro-n-propyh-(ybromo-n-propyl trithiolophosphite;-chloro-n-propyl) di-('y-bromo-n-propyl)dithiolophosphite;tri-('y-chloro-npropyl) ('y-bromoisopropyl) monothiolophosphite; di-(ychloro-n-butyl) ('y-bromo-n-butyl) trithiolophosphite; di-

('y-chloro-n-butyl) (y-bromo-n-butyl)dithiolophosphite; di--chloro-n-butyl) ('y-bromo-n-butyl) monothiolophosphite;tri-(a-bromoethyl)trithiolophosphite;tri-(a-bromoethyl)dithiolopl1osphite; andtri-(a-bromoethyDmonothiolophosphite; andtri-(y-bromopropyl)-trithiolophosphite.

In addition to the phosphites as hereinabove defined,'

the compounds of the present invention contemplate phosphates andthionophosphates. Thus, in considering the tribromoaliphatic embodimentof this invention, by appropriate choice of reactants phosphates asfollows can be provided: tribromoaliphatic thionophosphates,tribromoaliphatic trithiolothionophosphates, tribromoaliphaticmonothiolophosphates, tribromoaliphatic dithiolophosphates,tribromoaliphatic trithiolophosphates, tribromoaliphaticmonothiolothionophosphates, and tribromoaliphaticdithiolothionophosphates. Typical examples of such compounds of thepresent invention include tri- (fi-bromoethyl)thionophosphate; tri (Bbromoethyl)- monothiolophosphate; tri-(B-bromoethyl)dithiolothionophosphate; tri-(p-bromoethyl)trithiolophosphate;tri-(fibromoethyl)dithiolophosphate; tri-(,B-bromo-n-propyD-thionophosphate; tri-(fi-bromo-n-propyl)monothiolophosphate;tri-(fl-bromo-n propyl)dithiolothionophosphate; tri- (ti-bromo-n-propyl)trithiolophosphate; trifi-bromon-propyl) dithiolophosphate;tri-(fl-bromoisopropyl) thionophosphate; tri-(Bbromoisopropyl)monothiolophosphate; tri(/3-bromoisopropyl)dithiolothionophosphate; tri- (B-bromoisopropyl)trithiolophosphate; trifi-bromoisopropyl) dithiolophosphate;tri-(fi-bromo-n-decyl)thionophosphate;tri-(B-bromo-n-decyl)monothiolophosphate; tri (5bromo-n-decyl)dithiolothionophosphate;tri-(flbromo-n-decyl)trithiolophosphate; andtri-(fi-bromo-ndecyl)dithiolophosphate. The corresponding mixed halogencompounds having bromine plus a dissimilar halogen in the molecule arealso contemplated in the present invention.

The phosphate embodiment of the bromoaliphatic esters of thesulfur-containing monomeric acids of phosphorus can be prepared by twomethods. One method for the preparation of the phosphates of thisinvention comprises reacting a compound of the formula RiCHCHRz whereinX is oxygen or sulfur with a phosphorus halide of the formula wherein mis an integer from zero to 3 inclusive and R and R are organic radicals.

A second method of preparing the phosphates of this invention comprisesfirst forming a phosphite as defined hereinabove and including thetrioxy bromoaliphatic phosphites and concurrently or subsequentlyreacting said phosphites or thiolophosphites with an oxidizing agent orsulfur. Among the oxidizing agents which can be employed are thefollowing: oxygen, sulfur trioxide, sulfuric acid, vanadium pentoxide,nitrogen oxide, nitric acid, hydrogen peroxide, sodium peroxide, leaddioxide, persulfuric acid, ammonium persulfate, sodium perborate,potassium permanganate, and others.

To prepare the thionophosphates by this method it is suflicient toinclude in the reaction mixture or after formation of the phosphite orthiolophosphite elemental sulfur in any one of the various forms inwhich elemental sulfur occurs. The following examples illustrate meansof preparing representative members of the classes of compounds of myinvention.

Example I To 271 parts of phosphorus tribromide in a reaction vesselequipped with mechanical agitator and liquid inlet means is added 189parts of ethylene sulfide over a period of minutes at a temperature of10 C. After further reaction for 30 minutes the product,tri-(fl-bromoethyl) trithiolophosphite, is recovered in high yield.

Example 11 By the same procedure as Example I except that the reactiontemperature is 20 C. propylene sulfide is reacted with phosphorusdichloride bromide. A good yield of 13- (bromopropyl -di-B-chloropropyl) trithiolophosphite is obtained.

Example Ill By the procedure of Example I a mixture of 66 parts ofethylene oxide and 90 parts of ethylene sulfide are reacted with 271parts of phosphorus tribromide. A product comprising tri-(fl-bromoethyl)monothiolophosphite and tri-(B-bromopropyl) dithiolophosphite isobtained in good yield.

Example 1V Four hundred seventeen parts of 1,3-trimethylene bromohydrinare added over a period of 120 minutes to 271 parts of phosphorustribromide, with the temperature being gradually raised over this periodfrom 20 to 75 C. A stream of nitrogen is bubbled through the reactionmixture during the entire reaction period to remove hydrogen bromide byentrainment. At the end of the reaction period the mixture is found tocomprise tri-(ybromopropyl) trithiolophosphite.

Example V A mixture of 451 parts of tri(,B-bromoethyl) phosphite and 32parts of elemental sulfur are heated together for a period of 120minutes. At the end of this time the reaction mixture is cooled andfiltered to remove unreacted sulfur. The filtrate comprises tri-(,B-bromoethyl) thionophosphate in good yield.

Example VI Tri-(fi-bromoisopropyl) tn'thiolophosphite is oxidized bybubbling air through it at a temperature of 20 C. for 180 minutes in thepresence of sulfur trioxide. At the end of this time the mixture isfound to comprise tri- (B-bromoisopropyl) trithiolothionophosphate ingood yield.

Example VII To 303 parts of thiophosp'horyl bromide in a reaction vesselequipped with mechanical agitator and liquid inlet means is added 174parts of propylene oxide over a period of 80 minutes, the temperaturebeing gradually raised from 20 to 80 C. Ten parts of phosphorustribromide are present as a catalyst. At the end of this time thereaction mixture is found to comprise a mixture oftri-(B-bromo-n-propyl) thionophosphate and tri-(B- bromoisopropyl)thionophosphate in good yield.

The compounds of the present invention find special utility in the fieldof fuel additives, particularly as components of leaded fuels forspark-fired internal combustion engines, especially compositionscomprising a petroleum hydrocarbon fuel; an organolead antiknock agentsuch as tetraethyllead, tetrapropyllead and tetraphenyllead and thelike; halogen scavengers such as ethylene dichloride, ethylenedibromide,trichlorobenzenes, tribromobenzenes and the like; and my new compoundsbromoalkyl aliphatic esters of sulfur containing monomeric acids ofphosphorus wherein said sulfur is directly bonded to phosphorus.

The following example illustrates the effectiveness of my compound incombatting wild ping which is depositinduced autoignition difierent fromordinary engine knock. It occurs as an erratic uncontrolled ignitionoccurring at a different period in the combustion cyclic than ordinarycombustion induced by the spark.

Example VIII A series of commercial hydrocarbon fuels containing aconventional antiknock mixture comprising tetraethyllead (3 ml. pergallon of fuel), ethylene dichloride and ethylene dibromide are treatedas follows: to fuel I is added 0.9 gram per gallon oftri-(B-bromopropyl) trithiolophosphite, to fuel II is addedtri-(fl-bromoethyl) monothiolophosphite, to fuel III is added 0.9 gramsper gallon of di-(fi-bromoisopropyl)-(/3-ch1oro-n-propyl)trithiolophosphite, to fuel IV is added 0.9 gram per gallon oftri-(fl-bromoethyl) monothiolophosphate, to fuel V is added 0.9 gram pergallon of tri-(fl-bromopropyl) thionophosphate. Fuel VI is leftuntreated to act as a basis of comparison. Each of the above six fuelsis then separately subjected to a test procedure involving the use of asingle cylinder test engine equipped with an L-head cylinder and anelectronic wild ping counter which records the total number of wildpings which occurred during the test period. The electronic counter,which is used in conjunction with an ionization gap, automaticallydetects and records uncontrolled combustion (wild ping). In this testeach of the five fuels containing one of my new compounds reduces wildping substantially 50 percent as compared with the same fuel (fuel VI)containing antiknock mixture but not my compound.

The bromine-containing phosphorus compounds of my invention find utilityas fuel additives both when used alone and when used in admixture withany or all of their isomers as well as when used in admixture with otherphosphorus-containing materials. When my compounds are so used, theyshould be used in amount such that the total amount of phosphoruspresent in the gasoline is in the range of from about 0.05 to about 0.5theory of phosphorus. A theory of phosphorus is defined as the amount ofphosphorus theoretically required to react with the lead to form leadorthophosphate; namely, two atoms of phosphorus per every three atoms oflead. In addition to the antiknock and fuel compositions disclosedabove, my compounds are also useful in connection with other fuels andantiknock mixtures, such as those disclosed in U. S. 1,592,954;1,668,022; 2,364,- 921; 2,398,281; 2,479,900; 2,479,901; 2,479,902;2,479,- 903; and 2,496,983. When used in connection with organoleadantiknock mixtures, quantities of lead up to about 6.3 g. per gallon arepreferred.

My bromine-containing esters of phosphorus wherein sulfur is directlyattached to a phosphorus atom are especially beneficial as gasolineadditives, due to the co operation of the bromine and phosphorus atoms.

I claim:

1. As a composition of matter, a tri(13-bromo-aliphatic) thionophosphatehaving the formula wherein R and R are selected from the groupconsisting of hydrogen atoms and lower alkyl radicals.

2. As a composition of matter, tri(,B-bromo-is0propyl) thionophosphatehaving the formula CHO P=S CHZBI' 3 OTHER REFERENCES Chem. Abst., v. 42,p. 1558 (1948). Kosolapoft, Organo Phosphorus Compounds, page (1950).

1. AS A COMPOSITION OF MATTER, A TRI(B-B ROMO-ALIPHATIC) THIONOPHOSPHATEHAVING THE FORMULA